Story

Contents

System Diagram

I want to make a watch, that can check my location and time. So I decided to make this watch using Wi-Fi module (WizFi250) and Cortex-M0 MCU (WIZwiki-W7500). For getting geolocation of this watch, I used ip-api.com which is a geolocation server and I used NTP server for getting the current time. This picture is the system diagram of my project.

Hardware Configuration

UART0 RX/TX/CTS/RTS pins of WIZwiki-W7500 board are used to control WizFi250 which Wi-Fi module and It use I2C SDA/SCL pins for using SSD1306 OLED.

Compile WizFi250 Geolocation and NTP Example

You can use this application if access to this link and there are library which this example used.

SSD1306 Library

For using SSD1306 OLED, I used Adafruit GFX Library. While I used this library, I found bug about display function. So I modified this bug and I send “Pull Request” to origin author.

HTTP Client

I used HTTP Client Libary for getting geo-location information. This library is used to send or receive from web server. In this example, I connected to ip-api.com and then I can get geo-location information which CSV format. It had latitude, longitude and TimeZone. This is URL for this library: HTTP Client Library

NTP Client

I used NTP Client Library for using UDP communication. I can get UTC (Coordinated Universal Time) from NTP Server using this library. In this example, I used kr.pool.ntp.org which NTP Server of Korea and I added 9 hours to UTC for using Korea time: NTP Client Library